The Chancellor appeared to mouth the offensive comment in the direction of MP Andrea Jenkyns after she questioned Theresa May’s Brexit plans during Prime Minister’s Questions in Parliament on Wednesday.

Ms Jenkyns asked the Prime Minister: “At what point was it decided Brexit meant Remain?”

Mr Hammond is then said to have mouthed “stupid woman” from the front bench as a smiling Mrs May replied to Ms Jenkyns’.

Home Secretary Sajid Javid could be seen staring at Mr Hammond with concern after he made the jibe.

Ms Jenkyns’ fellow backbench Brexiteer Jacob Rees-Mogg said: “I cannot believe that the Chancellor would say something so rude – not only to Andrea but effectively to all Brexit voters.”

Ms Jenkyns, who quit her junior government role as a parliamentary private secretary in order to speak freely about Brexit, has since dismissed the furor over the comment, calling it “part of the cut and thrust of politics”.